1. Field of the Invention
The present invention relates to a fuel supply system of an engine provided with a pressure control means which controls a fuel pressure in an accumulator, on a pressurized fuel pathway sending pressurized fuel from a feed pump via a supply pump equipped with a plurality of plungers to the accumulator.
2. Related Art
Conventionally, there are well-known supply pumps, comprising a plunger for sending highly-pressurized fuel by pressurizing in a pressurizing chamber to an accumulator, so as to supply the fuel from a fuel supply system of an engine and a pressure control means which controls a fuel pressure in the accumulator by adjusting inhalation volumes of the fuel to the pressurizing chamber or pressurized volumes of the fuel from the pressurizing chamber by the plunger, wherein the inhalation volume of the fuel to the pressurizing chamber or the pressurized volume of the fuel from the pressurizing chamber is adequately adjustable by the pressure control means, so as to control the fuel pressure in the accumulator to a given pressure (for example, see JP2000-356156).
However, in the conventional fuel supply system, the inhalation volumes of the fuel to the pressurizing chamber or the pressurized volumes of the fuel from the pressurizing chamber by the respective plungers are adjusted using one pressure control means, and in this case, if the pressure control means is out of action due to a failure or the like, the fuel can not be supplied to the pressurizing chamber, thereby causing the problem on which the pressurized fuel can not be sent from any pressurizing chamber to the accumulators When this problem is due to the failure of the pressure control means itself, the fuel supply system can be constructed so that pressure control means are provided based on the number of plungers, and the inhalation volumes of the fuel to every pressurizing chamber or the pressurized volumes of the fuel from every pressurizing chamber by the respective plungers are independently adjusted using the respective pressure control means, whereby some of the fuel can be sent from the pressurizing chambers to the accumulators, unless all pressure control means break down. However, due to the above construction, the number of components in the supply pump are increased, thereby causing another problem of increasing the cost.